Description
The TP53 p.Arg282Gln variant was identified in 4 of 6032 proband chromosomes (frequency: 0.0007) from individuals or families with neuroblastoma, breast cancer, lung cancer, or Lynch syndrome (Chrompret 2000, Meric-Bernstam 2016, Tung 2016, Yurgelun 2015). The variant was also identified in dbSNP (ID: rs730882008 as "With Likely pathogenic, Pathogenic allele"), ClinVar (2x as pathogenic by Invitae and Ambry Genetics; 2x as likely pathogenic by ARUP Laboratories and Integrated Genetics/Laboratory Corporation of America; and 1x as uncertain significance by GeneDx), Cosmic (37x in Skin, Bone, Hematopoietic and lymphoid tissue, Upper aerodigestive tract or Large intestine), and the IARC TP53 Database (identified 2x in germline and 30x as somatic; classified as partially functional). The variant was not identified in the GeneInsight-COGR or LOVD 3.0 databases. The variant was identified in control databases in 2 of 277176 chromosomes at a frequency of 0.000007 (Genome Aggregation Database Feb 27, 2017). The variant was observed in the following populations: European Non-Finnish in 1 of 126670 chromosomes (freq: 0.000008) and Finnish in 1 of 25792 chromosomes (freq: 0.00004), while the variant was not observed in the African, Other, Latino, Ashkenazi Jewish, East Asian, or South Asian populations. Multiple studies using a yeast functional reporter assay have classified this variant as loss of function and concluded that this variant does not possess dominant negative activity (Hassan 2008, Shi 2002). The p.Arg282 residue is conserved across mammals and other organisms, and 4 of 5 computational analyses (PolyPhen-2, SIFT, AlignGVGD, BLOSUM, MutationTaster) suggest that the Arg282Gln variant may impact the protein; this information alone is not predictive enough to assume pathogenicity. However, the residue is located in the DNA-binding domain of TP53 and the Arg282Gln variant has been shown to accelerate the protein unfolding rate, possibly facilitating loss of protein function (Butler 2005). In summary, based on the above information this variant meets our laboratory’s criteria to be classified as pathogenic.
| # | Sample | Method | Observation |
|---|
| Origin | Affected | Number tested | Tissue | Purpose | Method | Individuals | Allele frequency | Families | Co-occurrences |
|---|
| 1 | unknown | yes | not provided | not provided | not provided | | not provided | not provided | not provided | not provided |
